1. Field of the Invention
The present invention relates to a joint structure for a fiber reinforced resin and a metal.
2. Description of the Related Art
Fiber reinforced plastics (FRPs) are today used widely in structural members for aircraft, automobiles, ships, and general industrial instruments. For example, a known structural member is formed by impregnating a woven fabric, in which inorganic reinforcing fibers such as carbon fibers or glass fibers are arranged in a crisscross pattern and interwoven, with a resin such as epoxy resin, and then hardening the resin. In many cases, however, such structural members are not formed entirely from fiber reinforced plastics, and a metallic material must be applied partially thereto. In a known technique employed in such cases, as shown in FIG. 6, for example, a fastener joint is formed between a fiber reinforced plastic 100 and a metallic material 101 using a fastening tool 102 so that the fiber reinforced plastic 100 and the metallic material 101 are firmly integrated.
When the fastening tool 102 is attached, however, a current generated by lightning or electrification, for example, may cause spark discharge F in a projecting portion of the fastening tool 102, and therefore the fastening tool 102 is preferably not used.
In recent years, a technique of directly adhering a fiber reinforced plastic and a metallic material to ensure that the fiber reinforced plastic and the metallic material are joined with a high degree of strength has been proposed. In so doing, the fastening tool 102 may be omitted, and as a result, a reduction in weight and so on can be achieved. Further, a technique of forming projections on a metallic material side joint surface serving as part of a joint surface between the fiber reinforced plastic and the metallic material in order to improve the strength of the joint between the fiber reinforced plastic and the metallic material has been developed (see Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2006-501070, for example).
With the joint structure using the fastening tool 102, however, an overall conductivity increases, and therefore a current generated by lightning or electrification can be expected to flow away smoothly, but when the fastening tool 102 is omitted, the conductivity inevitably decreases, and as a result, it may be impossible to remove the current smoothly.